No Working Group A. Galis Internet-Draft University College London Intended status: Informational J. Dong Expires: July 23, 2017 K. Makhijani S. Bryant Huawei Technologies January 19, 2017 Network Slicing - Introductory Document and Revised Problem Statement draft-gdmb-netslices-intro-and-ps-00 Abstract This documents represents an introduction to the motivation and Network Slicing problems and work ares. It represents an initial revision of Network Slicing problem statement derived from the analysis of the technical gaps in IETF protocols ecosystem. It complements and it bring together the isolated efforts being carried out in several IETF working groups to achieve certain aspects of network slice functions and operations. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on July 23, 2017. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents Galis, et al. Expires July 23, 2017 [Page 1] Internet-Draft NS Intro and PS January 2017 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Suggested Problems and Work Areas . . . . . . . . . . . . . . 4 2.1. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Documents . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Security Considerations . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References . . . . . . . . . . . . . . . . . . 8 7.2. Informative References . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction Network slicing (NS) refers to the managed partitions of physical and/or virtual network resources, network physical/virtual and service functions that can act as an independent instance of a network and/or as a network cloud. Network resources include connectivity, compute and storage resources. Slices considerably transform the networking perspective by abstracting, isolating, orchestrating, softwarizing and separating logical network components from the underlying physical network resources and as such they enhance Internet architecture. For slice creation, the management plane creates the grouping of physical and virtual network resources, connects with the physical and virtual network and service functions as appropriate and it instantiates all the network and service functions assigned to the slice. On the other hand for slice operations the slice control takes over the control and governing of all the network resources, network functions and service functions assigned to the slice, and (re-) configure them as appropriate and as per elasticity needs in order to provide an end-to-end service. Network operators can exploit NS to significantly reduce operations expenditures, and enable softwarization, programmability and the innovation necessary to enrich the offered services. Network softwarization techniques [IMT2020-2015], [IMT2020-2016] may be used Galis, et al. Expires July 23, 2017 [Page 2] Internet-Draft NS Intro and PS January 2017 to realised and manage [MANO-2014] network slicing. NS provides the means for the network operators to provide network programmable capabilities to OTT providers and other market players without changing their physical infrastructure. NS enables the concurrent deployment of multiple logical, self-contained and independent, shared or partitioned networks on a common infrastructure. Slices support also dynamic multi-services, multi-tenancy and the integration means for vertical market players. The purpose of NS work in IETF is to develop a set of protocols and/ or protocol extensions that enable efficient slice creation, activation / deactivation, composition, elasticity, orchestration, management, isolation, guaranteed SLA and safe operations within a network or network cloud / data centre environment that assumes an IP and/or MPLS-based underlay. While there are, isolated efforts being carried out in several IETF working groups DETNET, [I-D.leeking-actn-problem-statement], [I-D.dong-network-slicing-problem-statement], [I-D.galis-anima-autonomic-slice-networking], [IETF-Slicing1], [IETF-Slicing2], [IETF-Slicing3], [IETF-Slicing4], [IETF-Slicing5] to achieve certain aspects of network slice functions and operations, there is a clear need to look at complete life-cycle management characteristics of network Slicing solutions though the discussions based on the following architectural tenets: o Underlay tenet: support for an IP/MPLS-based underlay data plane the transport network used to carry that underlay. o Governance tenet: a logically centralized authority for network slices in a domain. o Separation tenet: slices are independent and have appropriate degree of isolation (1) from each other. o Capability exposure tenet: each slice allows third parties to access via APIs information regarding services provided by the slice (e.g. connectivity information, QoS, mobility, autonomicity, etc.) within the limits set by the operator. NS approaches that do not adhere to these tenets are explicitly outside of the scope of the proposed work at IETF. In pursuit of the solutions described above, there is a need to document an architecture for network slicing within both wide area network and a data center environments. Galis, et al. Expires July 23, 2017 [Page 3] Internet-Draft NS Intro and PS January 2017 Elicitation of requirements ([RFC2119], [RFC4364]) for a network slice control and management planes and will be needed facilitating the selection, extension, and/or development of the protocol for each of the functional interfaces identified to support the architecture. Additionally, documentation on the common use-cases for slice validation for 5G is needed (e.g. mission-critical ultra-low latency communication services; massive-connectivity machine communication services - smart metering, smart grid and sensor networks; extreme QoS; Independent operations and management; Independent cost and/or energy optimisation; Independent multi-topology routing; multi-tenant operations, etc.). The proposed NS work would be co-ordinated with other IETF WGs (e.g. TEAS WG, DETNET WG, ANIMA WG, NETCONF WG, SUPA WG, NVO3 WG, Routing Area WG (RTGWG), Network Management Research Group (NMRG) and NFV Research Group (NFVRG)) to ensure that the commonalities and differences in solutions are properly considered. Where suitable protocols, models or methods exist, they will be preferred over creating new ones. 1.1. Notes (1) This issue require efficient interaction between an upper layer in the hierarchy and a lower layer for QoS guaranties and most of the operations on slicing. 2. Suggested Problems and Work Areas The goal of this work is to develop one or more protocol specifications (or extensions to existing protocols) to address the following problem areas. These problems were selected according to the analysis of the technical gaps in IETF protocols ecosystem. o Uniform Reference Model for Network Slicing; Describe all elements and instances of a network slice. Describe shared non-sliced network parts. o Slice Templates: Design the slices to different scenarios ([ChinaCom-2009], [GENI-2009], [IMT2020-2016bis], [NGMN-2016], [NGS-3GPP-2016], [ONF-2016]); an appropriate slice template definition that may include capability exposure of managed partitions of physical and/or virtual network resources (i.e. connectivity, compute and storage resources), physical and/or virtual network and service functions that can act as an independent network and/or as a network cloud. Galis, et al. Expires July 23, 2017 [Page 4] Internet-Draft NS Intro and PS January 2017 o Network slice expected capabilities (i.e. prioritization may be needed): * Four-dimensional efficient slice isolation with guarantees for isolation in Data / Control / Management / Service planes. Enablers for safe and efficient multi-tenancy in slices. * Methods to guarantee the end-to-end QoS of a slice. * Recursion - methods for NS segmentation allowing a slicing hierarchy with parent child relationships. * Efficiency in slicing: realize diverse requirements without re-engineering the infrastructure. * Customized security mechanisms per slice. * Enablers to manage the trade-offs between flexibility and efficiency in slicing. * Optimisation - methods for network resources automatic acquisition, global resource view formed; global energy view formed; Network Slice deployed based on global resource and energy efficiency; Mapping algorithms. * Monitoring status and behaviour of NS in a single and/or muti-domain environment. * Capability exposure for slices; APIs for slices. * Programmability and openness of network slices. o Network slice operations (i.e. prioritization may be needed): Galis, et al. Expires July 23, 2017 [Page 5] Internet-Draft NS Intro and PS January 2017 * Slice creation: slices in access, core and transport networks; slices in data centres, slices in edge clouds. * Slice life cycle management including creation, activation/ deactivation, protection (2) , elasticity (3), extensibility (4) , safety (5) , Sizing and scalability of the slicing model per network and per network cloud. * Autonomic slice management and operation (i.e. self-configuration, self-composition, self-monitoring, self-optimisation, self-elasticity are carried as part of the slice protocols). * Slice stitching / composition: Enablers for efficient stitching / composition/ decomposition of slices: - vertically (service + management + control planes) and/or - horizontally (between different domains part of access, core, edge segments) and /or - vertically + horizontally. * E2E wireline network segments and network clouds orchestration of slices ([GUERZONI-2016], [KARL-2016]). * Service Mapping: Dynamic Mapping of Services to slices; YANG models for slices. o Efficient enablers for Integration of above capabilities and operations. 2.1. Notes (2) Protection refers to the related mechanisms so that events within one slice, such as congestion, do not have a negative impact on another slice. (3) Elasticity refers to the mechanisms and triggers for the growth /shrinking of network resources, network and service functions. (4) Extensibility refers to the ability to expand a NS with additional functionality and/or characteristics or through modification of existing functionality/characteristics, while minimizing impact to existing functions. (5) Safety refers to the conditions of being protected against different types and the consequences of failure, error harm or any other event, which could be considered non-desirable. Galis, et al. Expires July 23, 2017 [Page 6] Internet-Draft NS Intro and PS January 2017 [GUERZONI-2016] [KARL-2016] 3. Documents The following are the proposed / expected / resulting documents with priority (I) or (II) (i.e. revised prioritization may be needed): o Agreed work plan o Slice template and reference model to IESG (Informational) o Slice life-cycle management model to IESG (Informational) o Requirements for a network slice control and management planes. o Common use-cases for slice validation for 5G o (I) Slice template and reference model. o (I) Four dimensional efficient slice isolation with guarantees for isolation in Data/ Control/ Management/ Service planes. o (II) Methods to guarantee the end-to-end QoS of a slice. o (I) YANG data model for slicing. o (I) E2E orchestration of slices. o (II) Customized security mechanisms per slice. o (I) Slice stitching / composition: enablers for efficient stitch / composition / decomposition of slices vertically, horizontally and vertically + horizontally 4. Security Considerations Security will be a major part of the design of network slicing. 5. IANA Considerations This document requests no IANA actions. 6. Acknowledgements Thanks to Sheng Jiang (Huawei Technologies) for reviewing this draft. Galis, et al. Expires July 23, 2017 [Page 7] Internet-Draft NS Intro and PS January 2017 7. References 7.1. Normative References [I-D.dong-network-slicing-problem-statement] Dong, J. and S. Bryant, "Problem Statement of Network Slicing in IP/MPLS Networks", draft-dong-network-slicing- problem-statement-00 (work in progress), October 2016. [I-D.galis-anima-autonomic-slice-networking] Galis, A., Makhijani, K., and D. Yu, "Autonomic Slice Networking-Requirements and Reference Model", draft-galis- anima-autonomic-slice-networking-01 (work in progress), October 2016. [I-D.leeking-actn-problem-statement] Lee, Y., King, D., Boucadair, M., Jing, R., and L. Contreras, "Problem Statement for Abstraction and Control of Transport Networks", draft-leeking-actn-problem- statement-03 (work in progress), September 2014. [IETF-Slicing1] "Presentations - Network Slicing meeting at IETF 97 of 15th November 2016", n.d., . [IETF-Slicing2] "Presentations - Network Slicing meeting at IETF 97 of 15th November 2016", n.d., . [IETF-Slicing3] "Presentations - Network Slicing meeting at IETF 97 of 15th November 2016", n.d., . [IETF-Slicing4] "Presentations - Network Slicing meeting at IETF 97 of 15th November 2016", n.d., . Galis, et al. Expires July 23, 2017 [Page 8] Internet-Draft NS Intro and PS January 2017 [IETF-Slicing5] "Presentations - Network Slicing meeting at IETF 97 of 15th November 2016", n.d., . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 2006, . 7.2. Informative References [ChinaCom-2009] "A. Galis et al - Management and Service-aware Networking Architectures (MANA) for Future Internet - Invited paper IEEE 2009 Fourth International Conference on Communications and Networking in China (ChinaCom09) 26-28 August 2009, Xi'an, China", n.d., . [GENI-2009] "GENI Key Concepts - Global Environment for Network Innovations (GENI)", n.d., . [GUERZONI-2016] "Guerzoni, R., Vaishnavi,I.,Perez-Caparros, D., Galis, A., et al Analysis of End-to-End Multi Domain Management and Orchestration Frameworks for Software Defined Infrastructures - an Architectural Survey", June 2016, . [IMT2020-2015] "Report on Gap Analysis", ITU-T FG IMT2020 , December 2015, . [IMT2020-2016] "Draft Technical Report Application of network softwarization to IMT-2020 (O-041)", ITU-T FG IMT2020 , December 2016, . Galis, et al. Expires July 23, 2017 [Page 9] Internet-Draft NS Intro and PS January 2017 [IMT2020-2016bis] "Draft Terms and definitions for IMT-2020 in ITU-T (O-040)", ITU-T FG IMT2020 , December 2016, . [KARL-2016] "Karl, H., Peuster, M, Galis, A., et al DevOps for Network Function Virtualization - An Architectural Approach", July 2016, . [MANO-2014] "Network Functions Virtualisation (NFV); Management and Orchestration v1.1.1.", ETSI European Telecommunications Standards Institute. , December 2014, . [NGMN-2016] "Hedmar,P., Mschner, K., et al - Description of Network Slicing Concept", NGMN Alliance NGS-3GPP-2016 , January 2016, . [NGS-3GPP-2016] "Study on Architecture for Next Generation System - latest version v1.0.2", September 2016, . [ONF-2016] "Paul, M, Schallen, S., Betts, M., Hood, D., Shirazipor, M., Lopes, D., Kaippallimalit, J., - Open Network Fundation document "Applying SDN Architecture to 5G Slicing", Open Network Fundation , April 2016, . Authors' Addresses Alex Galis University College London Email: a.galis@ucl.ac.uk Galis, et al. Expires July 23, 2017 [Page 10] Internet-Draft NS Intro and PS January 2017 Jie Dong Huawei Technologies Email: jie.dong@huawei.com Kiran Makhijani Huawei Technologies Email: kiran.makhijani@huawei.com Stewart Bryant Huawei Technologies Email: stewart.bryant@gmail.com Galis, et al. Expires July 23, 2017 [Page 11]